Life is chance. Life is only chance. Why the singularity of "a" chance? I would never normally say such a thing as a native speaker.
It might not be ideal as written in English. The meaning is clear from the Czech sentence, though, where it's also a pretty common phrase (probably from the popular song with the same name).
The existence of a Czech song doesn't make the English translation sound any better to me. However pleasant and lovely the original. Can someone please make it acceptable with "a".
I wrote “Life is just chance” and it was still wrong.Maybe if I used “but” it would have been OK, but I always use either “only” or “just” as a translation for “jen” in these Czech modules.